As President Trump deals with an international focus on climate change, his domestic agenda remains fixed on the controversy over his latest political attack on his Democratic rival, Joe Biden. Overnight, the President has denied trying to coerce Ukraine into investigating corruption allegations involving Senator Biden's son, but he's also wavered about whether he'd release a transcript of the relevant phone call with his Ukrainian counterpart. It's provided more fuel for the Democrats, as they renew calls for President Trump's impeachment. USSC senior lecturer David Smith is quoted in this report on ABC PM.